In the drilling industry, some down hole mud powered drilling motors require flexible shafts to connect the power producing rotors to stable output shafts. Limited radial space limits the shafts to sizes that are challenged by the output torque of the motor rotors. The flexible couplings have been a source of life limiting factors for such motors since their introduction in the drilling activity.
The couplings having rubbing surfaces are available in a sealed version and in an unsealed version. If unsealed, limited life has attended the usual high reliability. If sealed, the couplings have little wear and high reliability, while the seals last. They suffer serious wear and consequent damage when the seals fail. The seals have reliability problems and sealed coupling has a consequent lack of reliability.
Seal designs have been subject to many design efforts, yet the problem remains throughout the related drilling activities. Drilling activities are rather costly and reliability problems in the down hole assemblies produce unplanned costs that are reflected in the cost of petroleum produces.
The seal design disclosed herein is associated with existing coupling designs that function quite well as long as the seals last. The disclosure includes a satisfactory coupling of the jaw-clutch configuration, and it is being produced with that jaw-type coupling. The seal will be used with other types of couplings when testing operations are complete. The disclosure with the jaw-type coupling is not to be construed in a limiting sense. That is anticipated by and is reflected in the claims. In addition to coupling motor rotors to output shafts, flexible couplings are used between bearing supported output shaft members to allow the motor output shaft to function in bend motor bodies used in directional drilling activities. The disclosed seals will be used in such bent motors to seal the lower couplings when proven in the rotor and output shaft couplings.